BhG 18.15

syntax

naraḥ (a person) śarīra-vāṅ-manobhiḥ (with body, speech and mind) yat nyāyyam vā viparītam vā (which is right or wrong) karma (activity) prārabhate (he undertakes),
ete pañca (these five) tasya (of that) hetavaḥ (the causes) [santi] (they are).

grammar

śarīra-vāṅ-manobhiḥ	–	śarīra-vāk-manas 3n.3 m.; DV: śarīrena ca vācā ca manasā ceti – with body, speech and mind (from: √śṝ – to break, to crush, śarīra – easy to be destroyed, the body; from: √vac – to speak, vāk – speech; √man – to think, manas – the mind);
yat	–	yat sn. 2n.1 n. –which;
karma	–	karman 2n.1 n. – activity (from: √kṛ – to do);
prārabhate	–	pra-ā-√rabh (to reach, to undertake, to begin) Praes. Ā 1v.1 – he begins, he undertakes;
naraḥ	–	nara 1n.1 m. – a man, a person (from: nṛ – man, mankind);
nyāyyam	–	nyāyya 2n.1 n. – customary, right, usual, proper (from: √nī – to lead, nyāya – rule, manner, system);
vā	–	av. – or, and, on the other side, but even if, however;
viparītam	–	viparīta (vi-pari-√xi – to turn round, to return) PP 2n.1 n. – reversed, wrong, contrary;
vā	–	av. – or, and, on the other side, but even if, however;
pañca	–	pañca 1n.3 n. – five;
ete	–	etat sn. 1n.3 m. – these;
tasya	–	tat sn. 6n.1 m. – of that;
hetavaḥ	–	hetu 1n.3 m. – causes, motives, reasons;

textual variants

yat → hi (indeed);
karma prārabhate → yat karmārabhate (which activity he begins);
naraḥ → ‘rjuna (O Arjuna!);
karma prārabhate naraḥ → karma prārabhyate naraiḥ (activity begun by people);
nyāyyaṁ → nyāyaṁ (the rule);
nyāyyaṁ vā viparītaṁ vā → vāpi parītaṁ ca (or wrong and);
pañcaite → paṁca te (these five);

Śāṃkara

śarīra-vāṅ-manobhir yat karma tribhir etaiḥ prārabhate nirvartayati naraḥ nyāyyaṃ vā dharmyaṃ śāstrīyam, viparītaṃ vāśāstrīyam adharmyaṃ yac cāpi nimiṣita-ceṣṭitādi jīvana-hetus tad api pūrva-kṛta-dharmādharmayor eva kāryam iti nyāyya-viparītayor eva grahaṇena gṛhītam, pañcaite yathoktās tasya sarvasyaiva karmaṇo hetavaḥ kāraṇāni |

nanv etāny adhiṣṭhānādīni sarva-karmaṇāṃ nirvartakāni katham ucyate śarīra-vāṅ-manobhir yat karma prārabhata iti ? naiṣa doṣaḥ | vidhi-pratiṣedha-lakṣaṇaṃ sarvaṃ karma śarīrādi-traya-pradhānam | tad-aṅgatayā darśana-śravaṇādi ca jīvana-lakṣaṇaṃ tridhaiva rāśīkṛtam ucyate śarīrādibhir ārabhyata iti | phala-kāle’pi tat-pradhānaiḥ sādhanair bhujyata iti pañcānām eva hetutvaṃ na virudhyata iti |

Rāmānuja

tad idam āha
nyāyye śāstrasiddhe, viparīte pratiṣiddhe vā sarvasmin karmaṇi śarīre, vācike, mānase ca pañcaite hetavaḥ / adhiṣṭhānam śarīram; adhiṣṭhīyate jīvātmaneti mahābhūtasaṃghātarūpaṃ śarīram adhiṣṭhānam / tathā kartā jīvātmā; asya jīvātmano jñātṛtvaṃ kartṛtvaṃ ca, „jño ‚ta eva”, „kartā śāstrārthavattvāt ” iti ca sūtropapāditam / karaṇaṃ ca pṛthagvidham vākpāṇipādādipañcakaṃ samanaskaṃ karmendriyaṃ pṛthagvidham karmaniṣpattau pṛthagvyāpāram / vividhā ca pṛthakceṣṭā / ceṣṭāśabdena pañcātmā vāyur abhidhīyate tadvṛttivācinā; śarīrendriyadhāraṇasya prāṇāpānādibhedabhinnasya vāyoḥ pañcātmano vividhā ca ceṣṭā vividhā vṛttiḥ / daivaṃ caivātra pañcamam atra karmahetukalāpe daivaṃ pañcamam paramātmā antaryāmī karmaniṣpattau pradhānahetur ityarthaḥ / uktaṃ hi, „sarvasya cāhaṃ hṛdi sanniviṣṭo mattaḥ smṛtir jñānam apohanaṃ ca” iti / vakṣyati ca, „īśvaraḥ sarvabhūtānāṃ hṛddeśe ‚rjuna tiṣṭhati / bhrāmayan sarvabhūtāni yantrārūḍhāni māyayā//” iti / paramātmāyattaṃ ca jīvātmanaḥ kartṛtvam, „parāt tu tacchruteḥ” ityādyupapāditam / nanv evaṃ paramātmāyatte jīvātmanaḥ kartṛtve jīvātmā karmaṇy aniyojyo bhavatīti vidhiniṣedhaśāstrāṇy anarthakāni syuḥ // idam api codyaṃ sūtrakāreṇa parihṛtam, „kṛtaprayatnāpekṣas tu vihitapratiṣiddhāvaiyārthyādibhyaḥ” iti / etad uktaṃ bhavati paramātmanā dattais tadādhāraiś ca karaṇakalebarādibhis tadāhitaśaktibhiḥ svayaṃ ca jīvātmā tadādhāras tadāhitaśaktis san karmaniṣpattaye svecchayā karaṇādyadhiṣṭhānākāraṃ prayatnaṃ cārabhate; tadantaravasthitaḥ paramātmā svānumatidānena taṃ pravartayatīti jīvasyāpi svabuddhyaiva pravṛttihetutvam asti; yathā gurutaraśilāmahīruhādicalanādiphalapravṛttiṣu bahupuruṣasādhyāsu bahūnāṃ hetutvaṃ vidhiniṣedhabhāktvaṃ ceti

Śrīdhara

eteṣām eva sarva-karma-hetutvam āha śarīreti | yathoktaiḥ pañcabhiḥ prārabhyamānaṃ karma triṣv evāntarbhāvyam | śarīra-vāṅ-manobhir ity uktaṃ śārīraṃ vācikaṃ mānasaṃ ca trividhaṃ karmeti prasiddheḥ | śarīrādibhiḥ yat karma dharmyam adharmyaṃ vā karoti naras tasya karmaṇa ete pañca hetavaḥ |

Viśvanātha

śarīrādibhir iti śārīraṃ vācikaṃ mānasaṃ ceti karma trividham | tac ca sarvaṃ dvividham | nyāyyaṃ dharmyaṃ viparītam anyāyyam adharmyaṃ | tasya sarvasyāpi karmaṇa ete pañca-hetavaḥ |

Baladeva

śarīreti – nyāyyaṃ śāstrīyam, viparītam aśāstrīyam |